<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>边框</title>
</head>
<body>
<style>
  div{
      width: 200px;
      height: 200px;
      /*border-color: red;*/
      /*border-width: 10px;*/
      /*border-style: solid;*/
      /*      width  style  color   */
      border: 10px solid    red;
      border-top-color:blue;
      border-top-width:20px;
      border-top-style:dotted;
      border-left: 5px dashed green;
      border-bottom: 25px double yellow;
  }
</style>
<div>

</div>
</body>
</html>